lean2/src/library/normalize.cpp
2014-09-26 20:16:03 -07:00

59 lines
2 KiB
C++

/*
Copyright (c) 2014 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#include "util/name_generator.h"
#include "kernel/type_checker.h"
#include "kernel/instantiate.h"
#include "kernel/abstract.h"
#include "library/reducible.h"
namespace lean {
class normalize_fn {
std::unique_ptr<type_checker> m_tc;
name_generator m_ngen;
expr normalize_binding(expr const & e) {
expr d = normalize(binding_domain(e));
expr l = mk_local(m_ngen.next(), binding_name(e), d, binding_info(e));
expr b = abstract(normalize(instantiate(binding_body(e), l)), l);
return update_binding(e, d, b);
}
expr normalize_app(expr const & e) {
buffer<expr> args;
expr f = get_app_rev_args(e, args);
for (expr & a : args)
a = normalize(a);
return mk_rev_app(f, args);
}
expr normalize(expr e) {
e = m_tc->whnf(e).first;
switch (e.kind()) {
case expr_kind::Var: case expr_kind::Constant: case expr_kind::Sort:
case expr_kind::Meta: case expr_kind::Local: case expr_kind::Macro:
return e;
case expr_kind::Lambda: case expr_kind::Pi:
return normalize_binding(e);
case expr_kind::App:
return normalize_app(e);
}
lean_unreachable(); // LCOV_EXCL_LINE
}
public:
normalize_fn(environment const & env):m_tc(mk_type_checker(env, true)), m_ngen(m_tc->mk_ngen()) {}
expr operator()(expr const & e) { return normalize(e); }
expr operator()(level_param_names const & ls, expr const & e) {
return m_tc->with_params(ls, [&]() {
return normalize(e);
});
}
};
expr normalize(environment const & env, expr const & e) { return normalize_fn(env)(e); }
expr normalize(environment const & env, level_param_names const & ls, expr const & e) { return normalize_fn(env)(ls, e); }
}